The intermittent nature of most Renewable Energy Sources (RES) imposes difficulties in matching supply with demand and technical problems associated with weak grids. Energy storage may play a vital role in addressing these issues allowing for higher penetration of RES into weak electricity grids, especially in islands and isolated communities. The aim of STORIES project, which is co-financed by the Intelligent Energy Europe programme of the European Commission, is to provide suggestions for changes in policies and regulations covering RES installations and to promote the use of energy storage technologies in island grids based also on the assessment of economic aspects, such as internal and external costs of energy storage solutions in order to increase RES penetration. The main outcome of the project will be the development of a Roadmap for the promotion of hybrid RES-energy storage power systems, which may assist in overcoming barriers for higher RES penetration in European islands and boosting the respective RES electricity markets in these areas. In the present work, the introduction of hydrogen as a storage means and wind energy as an electricity production source into the power supply system of the Portuguese island Corvo in Azores is presented. A cost-benefit analysis is carried out in order to examine the proposed RES and Hydrogen power system from an economic, environmental and social perspective. The results indicate that a considerable RES penetration into the power system of Corvo island is feasible and entails convergence between the financial and social profitability showing alignment of private and social interest. Copyright (C) 2010, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.